Belt-tightener.



J. H. SEWALL.

BELT TIGHTENER.

I APPLICATION FILED APR. 5, 1912.

WITPh-I A w 3. LE mm 3. Q J m d i 4 WM 5 J. H. SBWALL.

BELT TIGHTBNER.

APPLICATION FILED APR. 5, 1912.

1,108,085. Patented Aug. 18, 1914.

2 SHEETSSHBET 2.

ing drawings,

similar parts.-

James H. sEwALL, or KEEINE,. NEW mm rsnmn BELT-TIGHTENEB.

To all whom it may concern:

' Be it known that I, JAMES H. SEW-ALL, Keene, in the county of. Cheshire and State of New Hampshire, States, have invented a new and useful Improvement in Belt-Tighteners, of which-the and exact descripto the accompanyforming apart of this specififollowing is a full, olear, tion, reference being had cation, in explaining its nature;

y invention: relates to a mechanism or device for regulating, taking up, or compensating" for slack; or variation in the tension of a belt or the like The essential object of my inventionis to provide such mechanism ordevice as will-be automatic in its operation and be controlled by the power or pull developed in the belt itself during its operation; and a mechanism or device also that is adapted to automatically regulate, take-up or. compensate for slack or variation in. the tension of a belt connecting pulleys the relative positions of which to one another become changed either by oneof said pulleys being brought nearer the other pulley or moved farther away therefrom;-

My-invention can best be seen and understood by reference to the drawings, in which Figure 1 shows the device in .side elevation. Fig. 2 is also a side elevation of the device, the parts thereof occupying a changed position from that shown in Fig. 1, and F 3 is a plan of the device. and 6 are views similarto Figs. 1, 2, and 3, respectively, illustrating a modified construction. i

V In the drawings :1 represents a shaft upon which is mounted a pulley 2 which for purposes of illustration will be termed the driving pulley.

3 represents the driven pulley and 4 the shaft of this pulley. For purposes of illustration this pulley is shown mounted between fixtures or uprights 5 through which the shaft 4 of the pulley extends.

6 represents the belt connecting the pulleys. Cooperating with the belt 6 are auxiliary or idler pulleys 7 and 8, respectively. These pulleys are arranged upon shafts 9 which extend through the respective pulleys and beyond the edges of the belt, the auxiliary pulleys being preferably made about the width of the belt. The auxiliary Specification of Letters Patent. Application filed A rils, 1912. I Serial KID-"688,578+ I p a citizen .of the Unitedconnecting pulleys orpivotally connected Figs. 4, 5 -t Patented Aug. 18', 1914.

or' idler pulleys are connected by arms or links which pivotally connect with the shafts 9 uponwhich the idler pulleys-are mounted; One means of securing such connection is by forming the ends of the arms or links sons to sli'p'over the projecting ends of' the shaft 9 and then securing them by cotter pins 11 or other suitable fastenings. Each of the idler pulleys is also pivotally supported by means-of links or arms secured to'some suitable support. According to the construction shown the idler pulley 7 is pivotally supported by arms or links- 12 which pivotally connect with the shaft 9 of thispulleyv by slipping over the projecting ends of the shaft outside the links 10 and between them and the cotter pins -11.- The opposite ends of the arms or links 12 are pivotally secured to the uprights 5. The idler pulley 8 is-pivotally supported or carried by 1 links or: arms 13 pivotally secured to the ends of the shaft 9 upon which this pulley is arrangedby the ends of the links fitting over the ends of. the shaft and between the ends of the links 10 and the cotter pins 11 retainingthe same. The. duter ends of these links are pivotally arranged to turn from the uprights 5. Both sets of links 12 and 13 are with the uprights by fixing the outer ends of the links to shafts 14 which are arranged to turn in and-between the uprights at points 15 and 16, respeetively. Each of these shafts 14 preferably bears a weight 17 fixed thereto in such manner as to counterbalance the weight of he idler pulleys and connecting links.

Having indicated the various elements .or parts, reference will now be made to the relative disposition and arrangement of these parts and also to the principles involved in connectionwith their mode of operation. This can best be seen and understood when interpreted in the light of various planes of which a represents a plane passing through the axes of the main pulleys; 1) represents a plane passing through angles to the plane a, and 0 represents a plane passing through the axis of the driven pulley 3 at right angles to the plane a.

It is first to be observed that the auxiliary or idler pulleys 7 and 8 located outside the belt are so connected by the links 10 as to normally flex the belt or form angles of fiexure in the oppositely running portions 20 and 21 thereof. In other words, the normal arrangement of the idler pulleys is such,

that the opposite runningptrtitins of; the belt before mentioned will, by the diiierences of pull or tension therein, cause or, tend to cause the respective pulleys to move in unison in a direction transverse thelplane a or,:that plane passing through the respective mainpulleys. that the portion of the belt running toward the driving pulley will during the operation of the pulleys ,andbelt be maintained under a greater tension than theoppomtely movin portions 210i the beltrunningofii the driving pulley. This is by reason .ofthepull of the d'riv-in pulley upon the belt and the amount of di erenceof tension upon the diiferent, portionsof the stood why in belt, the tendency of the belt to draw or bear harder against the idler pulley 7 than the portion 21 of! the belt against the pulley 8. 1 Accordingly the portion 20- of the belt bearing. against the ulley oth pulleys 7 and '8 an. a direction transverse the plane 'a. From this it is underthe normal arrangement of the parts the idler pulleys should be so connected and so cooperate with or engage the belt as to normally flex the same or form angles of flexure in the oppositely running portions 20-and 21 thereof' as above described. The auxiliary or idler-pulleys are also normally so supported and arrange that as they are moved by the belt in a direction transverse the plane a passing through the axes of the major pulleys"a s' aforesaid, they will also move in reverse or opposite directions longitudinal said plane, one in the direction of the plane I) or that plane passing through the axis of the pulley and the other idler pulley in the direction of the plane '0, or that plane which passes through the axis of the driven pulley at right angles to the plane a. obtained by so pivotally supporting therespective idler pulleys that as they are moved transversely as aforesaid, they will also'be induced to move on diilerent and reverse lines of curvature tending in the direction of the planes 6 and c as above indicated. As Ihave shown in Fig. 1 of the drawings this effect is obtained by pivoting the arms or links 12 and 13 bearing the respective idler pulleys at separate points outside the plane a whereby these links and the idler pulleys carried by them will be positively moved in the reverse directions above indicated as both idler pulleys are moved in unison in a direction transverse the plane a.- I prefer h t the points at which the arms or links 12 and 13 bearing the respective idler pulleys are pivotally sethe axes of "It is obvious I tension lH-bhOSQ. different parts of the belt will vary dependwill befor the portion 20 7 will, if the belt beflexed, act to move- 2 at right angles to the plane a,

This effect isr mes es cured shall be as oppositeside's of the plane a which extends through the axes of the major pulleys. 'I also prefer that the arms or links bearing the respective idler pulleys shall be of the same length and shall be pivotally secured at points lying within a plane extending at right angles to the plane a and also atpoints equidistant therefrom. For these reasons the arms are shown pivotally secured-at the points 15 and 16, respectively, and, when in normal position,

are-oppositely inclinedwith respect to the plane a; i r

- .Thus disposed and arranged the parts will operateas follows, and t will first be assumed,,that the major pulleys are in their normalgpositions of separation and that slack arises in thebelteither by reason of the major pulleys being brought nearer to 'gether, by themovement of one orboth pulleys or otherwise.- Immediately upon slack being -formed in the belt that P01171011 20 of the belt, running onto ley will draw harder against the idler pulley. 7 than the portion 21 of the belt runhing ofi the driving pulley will bear against the idler ulley 8. Thereupon both idler pulleys wi l'be moved in a direction transverse the plane a or a plane passing through the centers of"the...1najor ulleys with the effect that the angle in theb respective idler pulleys will become changed, the one becoming more obtuse, as the other becomes more acute, substantially as described in my Letters Patent of the United States No. 1,016,787, of February 6, 1912, and which tends to take up the slack in the belt (see Fig. 2). Another pronounced effect also takes place. As the idler pulleys are moved transversely as aforesaid they will also -move in arcs of circles around those points 15 .and 16 at which the respective arms or directions longituthe idler pulley 7 r 7), and the idler pulley 8 moving toward the plane 0 (see Fig. 2). As the idler pulleys are thus moved in opposite directions, while the distance separating the pulleys remains the same, that is, that distance defined 'by the links or arms 10 which connect the respective idler pulleys, yet that distance, at right anglesto the plane a, axes of the respective idler pulleys becomes less as the links 10 are inclined to the-plane a than when the pulleys were in their normal positions with said links substantially perpendicular to saidplane, so that the belt becomes distorted or bent by the idler pulleys'in reverse and opposite directions and any slack therein is taken up.

In some cases it is desirable to so arrange the major pulleys and belt connecting the ane a,

elt made by the.

which separates the the driving pullinks bearing them are pivoted, with the effect that said idler pulleys are moved in o posite .dinal of the pl 'moving toward the plane same that the major pulleys may be farther the difference in the tension in respective separated from one another during the opopposite running portions of the belt be eration of the belt. In such cases the belt tween said main pulleys for taking up varimust be made and arranged with such norable slack in said belt, said mechanism commal amount of slack in it as to allow the prising a pair of auxiliary pulleys engaging a major pulleys being farther separated. In said opposite running portions of the belt, 40

suchcase of course the slack will be norand means connecting and movably supportmally taken up by the mechanism above deing said auxiliary pulleys to turn about scribed and will permit of the major pulseoarate axes of which at least one axis lies lots being separated, the operation being outside a plane passing through the axes of 75 simply a reversal of that-above described. said main pulleys, whereby both auxlhary In other words, the normal disposition and pulleys may be moved by said difference in arrangement of the parts will be substantension in the same general direction transtially as shown in Fig. 2 which shows the verse said opposite running portions of the disposition and arrangement of the parts belt and with a simultaneous relative change 3% after taking up slack in the belt and which of position longitudinal said running porwill permit of the major pulleys being sepations of the belt. rated from one another or moved into posi- 2. The combination with a pair of main tions indicated in Fig. 1 when the operating pulleys and a belt connecting said pulleys, parts will simply be drawn back into the of mechanism automatically .controlled by 5 positions indicated in said Fig. 1. A furthe difference in the tension in respective ther advantage of the apparatus resides in opposite running portions of the belt be the fact that it will operate equally as well tween said main pulleys for taking up variwhether the belt be running in one direction able slack in said belt, said mechanism comor the other. prising a pair of auxiliary pulleys normally It is obvious that the construction and forming angles of fiexure in said opposite arrangement of the parts of the apparatus running portions of the belt, means conmay be varied without departing from its necting and movably supporting said auxilessential principles and mode of operation. iary pulleys to turn about separate axes of. 30 As an example I have shown in Figs. 4 and which at least one axis lies outside the plane '5 a construction and arrangement diflerent passing through the axes of said main pulfrom that shown in Figs. 1 and 2 though leys, whereby both auxiliary pulleys may with parts operating in "substantially the be moved by said difference in tension in same manner and according to the same the same general direction transverse said 35 principles as those before described. In opposite running portions of the belt and Figs. 4 and 5 all the parts are the same as with a simultaneous relative change of poin Figs. 1 and 2 excepting that the place sition longitudinal said running portions of and manner of pivotally supporting the the belt. links 12 and 13 which connect with and 3. The combination with a pair of main 40 carry the respective idler pulleys. Accordpulleys and a belt connecting said pulleys,

ing to the modified construction these links of mechanism automatically controlled by cross one another and connect respectively the difference in tension in the respective with the uprights 5 bearing the driven pulopposite running portions of the belt for ley in a manner just reverse to that shown taking up variable slack in said belt, said 45 in Figs. 1 and 2. In other words, the link mechanism comprising a pair of auxiliary 12 hearing the idler pulley 17 is extended pulleys engaging the opposite running poracross or beyond the plane a to connect with tions of the belt, and means connecting and theuprights at a point below said plane and movably supporting said auxiliary pulleys the link 13 bearing the idler pulley 8 is exto turn about separate axes lying respectended across the plane a to connect with tively without and on opposite sides of a the uprights above said plane. Eachof the plane passing through the axes of said main links 12 and 13 is also independently sepulleys, whereby both auxiliary pulleys cured to the uprights by studs 18 on which may be moved by said difierence in tension the links turn, while each of the links is in the same general direction transverse said extended by the stud 18 to which it is pivopposite running portions of the belt and in oted and bears upon its end a counterbalopposite directions longitudinal said runancing weight 19, the weights 19 performning portions of the belt. ing the same function as the weights 17 in 4. The combinationv with a pair of main the construction first described. pulleys and a belt connecting said pulleys, 30 Having thus fully described my invention, of mechanism automatically controlled by I claim and desire to secure by Letters Patthe difference in tension in the respective ent of the United States opposite running portions of the belt for 1. The combination with a pair of main taking up variable slack in said belt, said pulleys and a belt connecting said pulleys, mechanism comprising a pair of auxiliary 5 of mechanism automatically controlled by pulleys normally forming angles of flexure in said respective opposite running; portions of the belt, means connecting an movably supporting said auxiliary pulleys to turn about separate axes lying respectively without and on opposite sides of a plane passing m opposite running portions of the belt and in opposite directions longitudinal of said opposite runningportions of the belt.

5. The combination with a pair of main pulleys and a belt connecting said pulleys,

15 of mechanism automatically controlled by the difference in tension in the respective opposite running portions of the belt for taking up variable slack in said belt, said mechanism comprising a pair of auxiliary 2c pulleys engaging respectively opposite running portions of the belt, and means connecting and movably supporting said auxiliary pulleys to turn about separate axes lying respectively without and on opposite sides of a plane passing through the axes of said main pulleys whereby both auxiliary pulleys may be moved by said difierence in tension in the same general direction transverse said opposite running portions of the belt and in opposite direction longitudinal of said opposite running portions of the belt, the said means comprising links connecting said auxiliary pulleys to move in unison, and arms supporting said auxiliary pulleys respectively, said arms being pivotally mounted and normally oppositely inclined with respect to said plane.

JAMES H. SEWALL.

Witnesses:

JoHN E. R. Hams, M. E. FLAHERTY. 

